Sprout/sprout/detail/param_at.hpp
bolero-MURAKAMI b3bb8121e8 最初
2011-09-01 02:48:32 +00:00

37 lines
881 B
C++

#ifndef SPROUT_DETAIL_PARAM_AT_HPP
#define SPROUT_DETAIL_PARAM_AT_HPP
#include <cstddef>
#include <type_traits>
#include <sprout/config.hpp>
namespace sprout {
namespace detail {
template<typename R, typename T, typename... Values>
SPROUT_CONSTEXPR inline typename std::enable_if<
sizeof...(Values) == 0,
R
>::type param_at(
std::size_t n,
T const& v,
Values const&... values
)
{
return v;
}
template<typename R, typename T, typename... Values>
SPROUT_CONSTEXPR inline typename std::enable_if<
sizeof...(Values) != 0,
R
>::type param_at(
std::size_t n,
T const& v,
Values const&... values
)
{
return n == 0 ? v : sprout::detail::param_at<R>(n - 1, values...);
}
} // namespace detail
} // namespace sprout
#endif // #ifndef SPROUT_DETAIL_PARAM_AT_HPP